Floating roof penetrations with reduced vapor space seal

Abstract

An improvement in a storage tank for a liquid having a floating roof and at least one stationary vertical member penetrating the floating roof through a well defined by an opening therein surrounded by a well wall partially in and partially above the level of a liquid stored in the tank, with the improvement being a vapor seal, covering the area between the vertical member and the well wall, positioned about at but above the liquid level in the well to thereby reduce the space in which vapor from the liquid can first accumulate and then be dispersed with vertical movement of the floating roof.

What is claimed is: 
     
       1. In a storage tank for a liquid having a floating roof and at least one stationary vertical member penetrating the floating roof through a well defined by an opening therein surrounded by a well wall partially in and partially above the level of a liquid stored in the tank, the improvement comprising: a vapor seal means covering the area between the vertical member and well wall positioned about at but above the liquid level in the well to thereby reduce the space in which vapor from the liquid can first accumulate and then be dispersed with vertical movement of the floating roof, with said seal means comprising a vertically displaceable shoe surrounding the stationary vertical member and a flexible membrane extending from the shoe to the well wall.